Snap buckles are commonly used as fastening means in waist bags which are frequently used by travelers, or in other bags and accessories. The snap buckle can usually be opened easily, or sometimes even accidentally without knowing by the user. It is not surprising that the snap buckle of a traveler's waist bag is unlocked by thieves without the knowledge of the user, especially in a crowded area.
It is disclosed in U.S. Pat. No. 7,219,406 a buckle with a safety latch to prevent the locking members from being disengaged in the locked position. Once buckled, the user has to manually set the safety latch to the secured position by moving a raised button. One disadvantage of the cited patent is that it requires an extra step from the user in locking the buckle, which is not convenient to the user. The user tends to forget to move the safety button when locking the buckle. Another disadvantage is that the user has to push down the raised button before releasing the raised button from the locked position to the disengaged position, which causes inconvenience to the user when unlocking the buckle.
The latch in the cited patent is disposed on the elongated bar of the male buckle member, which is a relatively fragile part due to its elongated shape and the slot therein for the latch to slide along. The latch being disposed on the elongated bar will make the elongated bar easy to break upon repeated use. The latch is exposed on the male buckle member, which makes it easy to be damaged and affects the look of the male buckle member.
In addition, in order to match with the male buckle member, the female buckle member has to further include a slot opening to receive the raised button on the latch. Therefore, the male buckle member is not compatible with any common female buckle member. A female buckle member compatible with the male buckle member of the cited patent has to be manufactured, which increases the manufacturing costs of the buckle.